1. Technical Field
The present invention relates to an actuator and a bonding apparatus and more particularly to an actuator which causes an object to move to an arbitrary position and to a bonding apparatus that includes a movement mechanism which causes a bonding part that performs bonding work to move to arbitrary positions.
2. Description of the Related Art
Bonding apparatuses such as wire bonders, die bonders and the like perform bonding work by causing a bonding tool attached to the tip end of a bonding head to move to arbitrary positions in a plane. Most of these bonding apparatuses comprise a so-called XY table in which an X table that is capable of moving only in the X direction and a Y table that is capable of moving only in the Y direction are stacked, and driving sources that drive these respective tables, as shown in Japanese Patent Application Laid-Open (Kokai) No. 2002-329772. In this bonding apparatus, the bonding tool can be moved to arbitrary positions in the XY plane by mounting the bonding head on an XY table, and driving the XY table by means of a driving source.
Furthermore, a technique in which a slide is caused to advance in a linear motion by a linear motor, and a rotary beam on the slide is caused to rotate by s second linear motor so that a capillary mounted on the rotary beam is positioned, is disclosed in U.S. Pat. No. 6,460,651.
There has been an increasing demand for high speed in bonding apparatuses; accordingly, there is a demand for high-speed positioning of the bonding head in arbitrary positions. From this standpoint, the prior art has the following problems:
In an XY table driving system, since the XY table has a stacked structure, the weight and inertia of the system tend to be large, so that there may be cases in which it is difficult to achieve the acceleration that is required for high-speed performance. Furthermore, depending on the position of the upper table, the driving source that drives the lower table may be unable to push against the center of gravity of the table, so that an unnecessary torque is generated. Accordingly, there may be cases in which the load on the guide mechanism such as the linear guide or the like is increased, so that high-speed positioning is hindered.
In the slide and rotary system disclosed in the U.S. Pat. No. 6,460,651, the response of the rotational movement is generally faster than the response of the linear movement. Accordingly, the high-speed characteristics tend to be improved compared to those of an XY table driving system. However, when the slide makes a linear movement, the rotational driving source makes no contribution to the propulsion in the X direction. Furthermore, in cases where it is attempted to mount the rotational driving source on the slide, this also acts in a direction that reduces the linear acceleration in the X direction.
In such prior art, since a moving mechanism with a stacked structure is used in order to obtain movement with two degrees of freedom in the case of movement to an arbitrary position in the plane, there may be limits to the extent that the required acceleration can be achieved. In some cases, as a result of the presence of one driving source, there may be an action working in a direction that reduces the acceleration in other driving.